Tunnel boat



TUNNEL BOAT Filed April 11, 1930 MNMU,

, Patented od. 20, ,1931

Um'rasrA'rs 'DAVIDYW TAYLOR, or wAsHmeroN, DI'SmRICTfOE'QOLMB'm,1,'

TUNNEL '30111' Application filed ApriI 11,

VIn the screw propulsion of vessels, the water in the propeller race behind the screw has a sternward and a rotary motion. For most vess'els the propeller race is clear of the hull.V

Any structure built to regain en'ergy'that is usually carried off in the race must be fitted within the race,V There are, however, some vessels which give an opportunity to utilize the momentum of the race by structures around it. This'is notablythe case in tun nel boats.

In my application, Serial No. 864,494, filed May 1929, I have vutilized the diverging rear end of the tunnel of a tunnel boat,onV

wholly within the divergent portion of the lv rear end of the tunnel and that simultaneously stops rotation of the race anddevelops the' forwardly propellling pressure therefrom. For this` purpose' I preferably use fins or ribs fitted on the diverging surfacesof the:

rear ends of the tunnels aft of the propeller. which stop the rotaton of the race in the immediate Vicinity of the diverging surface rotary direction of movement' of the waterof the race and directit aft to raise the pressure on the diverging walls of the race and thereby obtain a usefulforwardly ,propelling action on the dverging sides. w i

Referring to the drawings, in which like parts are similarly designated:v

Figure 1 isA avertical section'on line 1-1 of Fig. 3 of -a tunnel showing my invention; Fig. 2 is a horizontal section online 2-2 of Fig. 1; Fig. 3 is an end elevation;V Fig. 4 is an end elevatio'n of a rear-end of a tunnel having elliptical section and diverging walls; w i

-forms of finsor ribs'. Referring to` Figures hangof the hull is indicate'd at and it car-; ries the tunnel 12 substantia'lly fr'ectangular l in cros`s-section',vopen at itsfront endv and has 'preferably-a circular portion 'l'in" which the propeller-'14 rotates'. i v ,Q 1The 'propeller is driven'by a `shaft 15.-

w [The tunnel isclosed Von all-four-sides,1has"`' side-Walls 16 diverging at ther'ear end.`v Only of the tunnel. These fins or ribs change the i `ed to"in`1ier,"diver`ging walls'of 'the tunneland theiraftends. i'

In'Fig`4'I have also on'lalli sides but ,substantiallyi'elliptica'l 'Min Fig z'p isa horizontal section of ai'ytunnel,v formed'by a depression in the'side'of a vessel andopenat'the'sidelofthe tunnxelufV 'Fig.'6 isanelevation-thereof; i

- i 'FigsI 8, v9 and 10 show VSections ;offdifierentV 1%8, the. sternffover- A the' 'side walls i diverge' to: reducei lthe f dra'ft i *ofi'th'e boat. Thes'fsid'e' walls' ;16, vcare pro- `vided with projecting'finfs, ribs'or plates 172,, ,preferably but not necessarily projecting beL 70. V`yond-th'e circular patlijo'ftips ofthe propel- 'ler blades.V 4

`The racefvleavihg the propeller 14 has fa rotaryflmov'ement and' encounters the' fins 17g.

Aon' lthe ,divergingi walls ofth'e' frear `Iend 'of-75 the tunn'el'that stop'rotation'lof 'the 'race or. that portion ofit'in the region-'oftheffins which direct'the wateraftalongthe divferg-` r ing alls of 'the tunnelon which,thejpressu`re;`

developsl :The pressure by" reason' of act'ingf'so on the walls'whichA are iriclinedV to the 'direc- 'tion in' which the pressure 'isdevelop'ed ex'erts a forwardly driving'componnt'useful in asi' sisting the propulsion of the vessel. I y

lThe fins, ribs orhplate may havevarious shapes'in cross section as vshown atf17,l 18, 1 9 in F igs '8, 9 and`10 respectively and'are generally Of'the'v Shape of thel angles fastenmay Vary in widthespecially i-n tunnelszsubfsta'nti'allyfrectangular in cross'section. InV j Fig.V 2'thesejfins17 increase in'widthtoward i showna tunnel closed 95 cross section :in it's'diverglng portionfl'G-a'having fins 17a directed radially.V

In'YFigs; 5,6, '7,'I'1have shown, aftunnel vfnned by fa' depressi'on'f aovi'n the? side O fa vesself and radial rbs in the'divergin'gjpor-` tion 21 just aft of the propeller. This tunnel tunnel, said tunnel having its two sides diis open at the side towards the Water. Vergng; of 'fins on the diverging sides ex- In any case whether thetunnel aft of'the tending from the propeller position aft that propeller is rectangular in cross-section, cirincrease in width.

5 Vcular,elliptical, entirely closed on its sides or n testimony that I claim the foregoing open at lone side, the fins are to be applied to as my invention, I have signed my name.. the divergingwalls: of the rearend of the i DAVID: .TAYLOR tunneliaft (if thew'propeller. v i i i I i In general wherever the propeller race fol-` 10 loWs a hull surface which is at such angle to the axis of the-race,-as'it leavesfthe'propeller that an increase of pressure would result in an increase of forward thrust upon the' hiill, the installation of finsrwill produce anHin-V' crease of pressure upon the hull, the installationf of' finsfxtoproducefan increase; of presv -Vsurefupontherlull 'surfaceby checkingz'the rotationfin thezrace will beadvantageousl o o 20 This localincreasez of pressure will` also o i cause-the race-to hug the'surface better and itristhis: indirectfaction of the fi-ns which is i particularly helpful i in diverging itunnels loe-V i -csonsebyreasonsof itthefwater more nearly maintains the pressure Velocityl relations ofa perfect flui'd, o and: the.. checking` of: the .stern- Wa17dvelocity1asthe tunnel expands results in 'f the; produc''ioin;` of xuseful forward thrust'. i'

Longitudinally the fins Jmay be'of-unirform 30 width orvnot. v:fFins-jinia circular diver'ging fi tunnehha-vef1ittlerto gain'by' Varying'width,

` Eig. 2; but: tlfiose` on: the ;s-ides of aa tunnel 'of approximatelyz'-reetangular section zimay `;be

. 'wdened towandxtheirafter ends'withzadvam 1 I a tunnel diverging at its rear end,fand;a pl'opel'er'in the tun'nel; fmeans inzsai'd diverg- 1 ing=l end to zsimultaneously check race; rota- W tion:andproduce a 'forwardly propell'ing h 'component :on the1 =diverging`fwallswf said f ;rear-endaftzof. the. pro-pellers. f ii i ;2. Snzatunnelboan-the combinationwith'a ;{timnel diverging' atz its ;zrear end; and a profpeller 2 ,the-ttunnel of means proj ecting from thesdiverging lwalls ofisaidtunnel'to pheckfracegrotationfand' simnltaneously .pro-v o i.

duce a'- forwardly. propell-ing, forcezon the 5 dverging'wallsV of; saidV reari end a'ft'- of: the

igro'peller.v o i Ina tunnel 'boat,.the combination 'W'ith F tunnel and-:a `propeller therein,=said tunnel Idiizeigfin';3 fromthe propeller' positionftozits :reareend of ifi'ns projecting' from thefdiverg- *55. ingwe-11sfot-said race.l w 4:.;Inza-'tunnel boat, thecombinationlwith -sartunnelm and a: propeller'therein, said. timnel diverging from the propeller'position-tofits y z rear end ;i of projeoting from the diverg- F260 ingwalls; ofsaizdace,V increasing inf' width from: the propellereposition to o the.l rear end ofthetunnel. i

gIn a-i-.tunnelboatfhaving:aV tunnel` substa-ntially: reotangiilar, in cross ;sectionfand '65 lessdi-Qn its iierssidesffapmpellesinwhe 

